But this is not to say I agree with your interpretation at all. Your
submission doesn't include the library, nor should it. It introduces a
dependency on that library, that's all.
"Supporting files" usually means files other than the program code
that are included in the program's release; it would not normally
include libraries that the program links with but that are not part of
its distribution. If people are worried about ambiguity in this
expression, I'm sure it will be easy to make the wording clearer.